For a variety of applications, used are functional members that include a base having a glaze layer and a photocatalyst layer provided on a surface of the glaze layer for utilizing the decomposition activity or hydrophilization activity of the photocatalyst. For example, sanitary wares that have been treated by forming a photocatalytic surface layer on a surface of sanitary wares are known. Such sanitary wares can suppress the deposition of contaminants thereon by a hydrophilic nature developed upon exposure of the photocatalyst layer to light, preferably ultraviolet light, and, at the same time, can suppress bacterial growth by photocatalytic decomposition activity. By virtue of these properties, a cleaning burden can be alleviated.
It is required for the photocatalyst layer provided on the base to have layer strength which is high enough to withstand a service environment and, further, water resistance and abrasion resistance. For sanitary wares, e.g., JP H11(1999)-228865A (PTL 1) proposes the use of titanium alkoxide and silicon alkoxide to enhance the layer strength of the photocatalyst layer. Further, JP H8(1996)-103488A (PTL 2) discloses gradually changing components in the photocatalyst for enhancing layer adhesion as an advantage. Some of the present inventors have proposed that a precursor of titanium oxide and a precursor of zirconium oxide are fired together to form a photocatalyst layer (PCT/JP2012/58114). These photocatalyst layers have a high level of water resistance and abrasion resistance while maintaining good photocatalytic activity. However, there is still a demand for photocatalyst members that have a high level of layer strength, water resistance, abrasion resistance and other properties while maintaining a high level of photocatalytic activity.